Antimicrobial therapy for acute cholangitis: Tokyo Guidelines

Antimicrobial agents should be administered to all patients with suspected acute cholangitis as a priority as soon as possible. Bile cultures should be performed at the earliest opportunity. The important factors which should be considered in selecting antimicrobial therapy include the agent's activity against potentially infecting bacteria, the severity of the cholangitis, the presence or absence of renal and hepatic diseases, the patient's recent history of antimicrobial therapy, and any recent culture results, if available. Biliary penetration of the microbial agents should also be considered in the selection of antimicrobials, but activity against the infecting isolates is of greatest importance. If the causative organisms are identified, empirically chosen antimicrobial drugs should be replaced by narrower-spectrum antimicrobial agents, the most appropriate for the species and the site of the infection.     

Erythropoietin: a possible cytoprotective cytokine in acute necrotizing pancreatitis

Background/purpose  Despite decades of research and clinical trials, a specific therapeutic treatment for acute pancreatitis (AP) has yet to be developed. The aim of the present study was to investigate the effects of erythropoietin on the severity of taurocolic acid-induced acute necrotizing pancreatitis. Methods  Forty-seven male Wistar albino rats were randomized into seven experimental groups. In group I, animals were sham-operated (n = 5). In groups II, III, IV, IIepo, IIIepo, and IVepo, AP was induced by sodium taurodeoxycholate treatment (n = 7). In groups II, III, and IV, 1 ml normal saline and in groups IIepo, IIIepo, and IVepo, 1000 U/kg body weight erythropoietin (EPO) was administered intramuscularly immediately after the induction of AP. Animals were killed at 24, 48, and 72 h postoperatively. Histopathological and biochemical evaluations were performed. Results  The serum levels of interleukin-6 (IL-6) and tissue levels of malondialdehyde were found to be significantly lower in EPO-administered groups when compared with the levels in groups without EPO treatment. The severity of pancreatic edema, acinar necrosis, inflammation, and perivascular infiltrate were reduced in all the EPO groups compared with the no-treatment groups. Conclusions  Our findings may reflect the possible cytoprotective effect of EPO in acute necrotizing pancreatitis.     

Cholesterol-mediated activation of P-glycoprotein: distinct effects on basal and drug-induced ATPase activities

Cholesterol promotes basal and verapamil-induced ATPase activity of P-glycoprotein (P-gp). We investigated whether these effects are related to each other and to the impact of the sterol on bilayer fluidity and verapamil membrane affinity. P-gp was reconstituted in egg-phosphatidylcholine (PhC) liposomes with or without cholesterol, 1,2-dipalmitoyl-phosphatidylcholine (DPPC), alpha-tocopherol (alpha-Toc) or 2,2,5,7,8-pentamethyl-6-chromanol (PMC). Basal and verapamil-induced ATPase activities were studied with an enzymatic assay. Membrane fluidity was characterized with diphenyl-hexatriene anisotropy measurements and membrane affinity by equilibrium dialysis. DPPC (70% mol/mol) decreased the fluidity of PhC bilayers to the same level as 20% cholesterol. PMC (20%) and alpha-Toc (20%) decreased the fluidity to lesser extents. alpha-Toc and PMC, but not DPPC increased the verapamil membrane affinity. While 20% cholesterol strikingly enhanced the basal ATPase activity, none of the other constituents had a similar effect. In contrast, verapamil stimulation of P-gp ATPase activity was not only enabled by cholesterol but also by alpha-Toc and DPPC. PMC had no effect. In conclusion, cholesterol exerts distinct effects on basal and verapamil-induced ATPase activity. The influence on basal ATPase activity is sterol-specific while its effect on verapamil-induced ATPase activity is unspecific and not related to its influence on membrane fluidity and on verapamil membrane affinity.     

Bond strength between root dentin and three glass-fiber post systems

STATEMENT OF PROBLEM: Glass-fiber posts were introduced for use after endodontic therapy instead of metal alloy and ceramic posts. There are several new types of glass-fiber post systems available, but little is known about how well these posts bond to the root surface. PURPOSE: The purpose of this in vitro study was to compare the bond strengths of 3 different types of glass-fiber post systems-opaque, translucent, and electrical glass-in 3 different locations of prepared post spaces. MATERIAL AND METHODS: Sixty human intact single-rooted extracted teeth were used. The root canals were prepared using a step-back technique and obturated with gutta-percha using lateral condensation. The roots were divided into 3 experimental groups and further divided into 2 subgroups according to testing time (n=10). Roots were restored with 1 of the following post systems according to the manufacturer's instructions: opaque glass-fiber posts (Snowpost), translucent glass-fiber posts (FiberMaster), and electrical glass-fiber posts (Everstick). A self-etching primer (Clearfil Liner Bond) was applied to the walls of the post spaces, allowed to etch for 30 seconds, and gently air dried. A dual-polymerized bonding agent (Clearfil Liner Bond, Bond A and B) was then applied to the same walls. A dual-polymerizing resin luting agent (Panavia F) was mixed for 20 seconds and then placed in the post spaces using a lentulo spiral instrument. The roots were placed in light-protected cylinders; then the light source was placed directly on the flat cervical tooth surfaces and the cement was polymerized. Specimens were stored in light-proof boxes for 24 hours or 1 week after the polymerization procedure. Each root was cut horizontally, and six 1-mm-thick root segments (2 apical, 2 middle, and 2 cervical) were prepared.Using a push-out test, the bond strength between post and dentin was measured after 24 hours or 1 week using a universal testing machine. Statistical analysis was performed with 3-way ANOVA followed by independent t tests (alpha=.05) to detect differences between groups defined by the specific interacting variables. The different combinations of posts and luting material from the cervical segments were analyzed with SEM. RESULTS: The 3-way ANOVA indicated that push-out test values varied significantly according to the post system used (opaque, electrical, and translucent) (P<.01); the root segments (cervical, middle, and apical) (P<.01), however, did not vary statistically according to the time of testing (24 hours and 1 week). Opaque and electrical glass-fiber posts showed higher bond strength values than translucent posts (P<.01). Push-out bond strength values of cervical segments were significantly higher than the middle and apical segments in translucent and electrical glass-fiber post groups (P<.01). In the opaque glass-fiber post group, there were no significant differences between cervical and middle segments. In SEM analysis, a distinct hybrid zone with long, numerous resin tags located between luting material and dentin was exhibited in all post systems. CONCLUSION: The opaque and electrical glass-fiber posts exhibited similar bond strengths, and translucent posts exhibited the lowest bond strength. The highest bond strength was observed in the cervical third of the post spaces for translucent and electrical glass-fiber post groups.     

The quantitative evaluation of apical sealing of four endodontic sealers

The aim of this in vitro study was to evaluate the apical seal obtained with four root canal sealers: Rocanal 2, Sealapex, AH Plus, and RC Sealer. Forty root canals were prepared using the step-back technique. The specimens were divided into four groups of 10 samples and obturated by laterally condensed gutta-percha with one of the tested sealers. The computerized fluid filtration method was used for evaluation of apical sealing properties. The quantitative apical leakage of each specimen was measured after 7, 14, and 21 days. Statistical analysis indicated that the apical leakage of all sealers used in this study decreased gradually from 7 days to 21 days (p < 0.05). Sealapex showed better apical sealing than the other sealers at 7, 14, and 21 days (p < 0.05). RC Sealer, AH Plus, and Rocanal 2 showed similar apical leakage values at every period (p > 0.05).     

Influence of the contact time on coupling time and a simple method to measure coupling time

The enhancement of performance in stretch shortening cycle (SSC) exercises has been attributed to the recoil of elastic energy stored during the stretching phase and depends on the duration of the coupling time (T _coupling) i.e., the duration of the isometric phase occurring between the stretch and the shortening of the muscle. However, instead of T _coupling, the contact time (T _contact)—i.e., the sum of T _coupling plus the duration of the stretching and shortening phases that precede and follow T _coupling—is more easily and often measured. The aim of this study was to investigate the T _coupling changes within a large range of T _contact, in order to propose a possible relationship between T _coupling and T _contact, thus allowing the accurate measurement of T _coupling only from a tachometer and force data obtained classically in vertical jumps, jumps on sledge apparatus and running on force treadmills. Eleven subjects performed SSC exercises on a sledge apparatus with a large range of T _contact (400, 700, 1,000, 1,500, 2,000 and 2,500 ms). The T _coupling and T _contact values were measured individually, from force platform recordings and the velocity of the carriage seat obtained by a tachometer. For the longest T _contact (i.e., from 850 to 2,500 ms), we observed a significant linear relationship between T _contact and T _coupling. This transition between T _contact shorter or longer than about 850 ms seems to be important and to correspond to T _coupling close to 300 ms. This limit observed in the present study could be explained physiologically due to a possible modification of the cross-bridges formation.     

Role of the C2 articular branches in occipital headache: an anatomical study

One of the most important structures involved in the pathogenesis of occipital headache is the lateral atlanto-axial joint. Previous studies demonstrated that injection of this joint with local anesthetic can alleviate occipital headache, while injection of contrast medium exacerbates it. The aim of our study is to improve the understanding of the nerve supply to the lateral atlanto-axial joint by the C2 nerve elements, in order to determine the optimal target for an anesthetic block of this area. Ten C2 spinal nerves and roots were dissected in five embalmed cadavers with the aid of a 40X microscope and the lateral atlanto-axial joint was shown to be extensively supplied by articular branches of C2 nerve elements (dorsal ganglion, spinal nerve, and ventral ramus). Following our observations on their distribution, we propose a target for local anesthetic injection of the C2 articular branches that is based on reliable landmarks and is easily identifiable at fluoroscopy. We suggest that local anesthetic injection at this target point could be of benefit in the relief of occipital pain due to cervical trauma or degenerative disease involving the lateral atlanto-axial joint.